XB6 or XB7 and-or with pods or modem + router or mesh system

My dilemma: new construction, 3 floors, with whole house wired (7 different wall plates throughout the house with a coax port and a blue cat 5(?) port) to a central location in the basement's Mech Room in the front of the house. Starting from scratch, so I know I need a lot of equipment, but the budget is not a concern -- if Xfinity for cable & internet (meh, whatever), do I go with an xFi gateway and-or pods or do I go with a standard modem and a suped-up router like those made by Netgear, Asus or a mesh system like a Nest, Eero? If so and I have any issues, will Xfinity hang up on me because I am not using/renting their equipment -- or is that just an old horror story?

One dumb question, will the gateway need to be located in the basement, next to this central location of black and blue wires? If so, my biggest concern is the reach to what will be my GF's office, 2 floors up, upstairs in the front of the house. Will a gateway be sufficient? Will pods help that far up and away from the gateway? Or should I set up that bedroom completely "wired" to the cat 5 port in the wall? Or is that cat 5 ultimately, too slow for matters such as WFH video conferencing? Apologize for dumb questions and-or incorrect usage of tech terms. Thanks.